Answer:
See below
Step-by-step explanation:
Part a)
Ba⁺²
Since it has a positive charge, this means it has lost electrons and that too 2 electrons. It has lost 2 electrons.
Part b)
As⁻³
Since it has a negative charge, it has gained electrons and that too 3 electrons. It has gained 3 electrons.
Part c)
Cu⁺²
It has a positive charge, so it has lost electrons and that too 2 electrons. It has lost 2 electrons.